Disclosed are intermediate transfer members, and more specifically, intermediate transfer members useful in transferring a developed image in an electrostatographic, for example xerographic, including digital, image on image, and the like, printers, machines or apparatuses. In embodiments, there are selected intermediate transfer members comprised of surface treated carbon black, which is subsequently dispersed in a polymer solution, such as a polyamic acid solution illustrated in copending applications U.S. application Ser. No. 12/129,995, U.S. Publication No. 20090297232, and U.S. application Ser. No. 12/181,354, U.S. Publication No. 20100028700, the disclosures of which are totally incorporated herein by reference. The carbon black can be treated with, for example, a poly(vinyltrialkoxysilane), and more specifically, a poly(vinyltriethoxysilane) (VTES), formed by the free radical polymerization of a vinyltrialkoxysilane, vinyltriethoxysilane, and the like.
A number of advantages are associated with the intermediate transfer member and belt (ITB) of the present disclosure, such as excellent primary size and aggregate size for the surface treated carbon black; dimensional stability; acceptable conductivities; a variety of formulation latitudes for the disclosed ITB as compared to an ITB with an untreated carbon black; ITB humidity insensitivity for extended time periods; excellent dispersability in a polymeric solution; low and acceptable surface friction characteristics; and a simplified economic ITB formation.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member, and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles and colorant, which are commonly referred to as toner. Generally, the electrostatic latent image is developed by bringing a developer mixture into contact therewith. The developer mixture can comprise a dry developer mixture, which usually comprises carrier granules having toner particles adhering triboelectrically thereto, or a liquid developer material, which may include a liquid carrier having toner particles, dispersed therein. The developer material is advanced into contact with the electrostatic latent image and the toner particles are deposited thereon in image configuration. Subsequently, the developed image is transferred to a copy sheet. It can be advantageous in some situations to transfer the developed image to a coated intermediate transfer web, belt or component, and subsequently transfer with high transfer efficiency the developed image from the intermediate transfer member to a permanent substrate, followed by fixing.
In electrostatographic printing machines wherein the toner image is electrostatically transferred by a potential difference between the imaging member and the intermediate transfer member, the transfer of the toner particles to the intermediate transfer member and the retention thereof should be substantially complete so that the image ultimately transferred to the image receiving substrate will have a high resolution. Substantially about 100 percent toner transfer occurs when most or all of the toner particles comprising the image are transferred and little residual toner remains on the surface from which the image was transferred.
Intermediate transfer members permit a number of advantages such as enabling high throughput at modest process speeds, excellent registration of the final color toner image in color systems using synchronous development of one or more component colors using one or more transfer stations, and increasing the range of final substrates that can be used. However, a disadvantage of using an intermediate transfer member is that a plurality of transfer steps occurs allowing for the possibility of charge exchange occurring between toner particles and the transfer member which ultimately can lead to less than complete toner transfer. The result is low resolution images on the image receiving substrate and image deterioration. When the image is in color, the image can additionally suffer from color shifting and color deterioration.
In embodiments, the resistivity of the intermediate transfer member is within a range to allow for sufficient transfer. It is also desired that the intermediate transfer member has a controlled resistivity, wherein the resistivity is substantially unaffected by changes in humidity, temperature, bias field, and operating time. In addition, a controlled resistivity is of value so that a bias field can be established for electrostatic transfer. Also, it is of value that the intermediate transfer member not be too conductive as air breakdown can possibly occur.
Attempts at controlling the resistivity of intermediate transfer members have been accomplished by, for example, adding conductive fillers, such as ionic additives and/or carbon black, to the outer layer. For example, U.S. Pat. No. 6,397,034 discloses the use of a fluorinated carbon filler in a polyimide intermediate transfer member layer. However, there are disadvantages associated with the use of such additives, such as the undissolved particles frequently bloom or migrate to the surface of the polyimide polymer and cause known imperfections in this polymer. This leads to nonuniform resistivity, which can cause poor antistatic properties and poor mechanical strength. More specifically, the ionic additives on the ITB surface may interfere with toner release; bubbles may appear in the conductive polymer, some of which can only be seen with the aid of a microscope, and others of which are large enough to be observed with the naked eye. These bubbles result in poor or nonuniform electrical properties and poor mechanical properties.
In addition, the ionic additives themselves are sensitive to changes in temperature, humidity, and operating time. These sensitivities often limit the ITB resistivity range. For example, the ITB resistivity usually decreases by up to two orders of magnitude or more as the humidity increases from about 20 percent to 80 percent relative humidity. This effect limits the operational or process latitude.
Moreover, ion transfer can also occur in these systems. The transfer of ions leads to charge exchanges and insufficient transfers, which in turn causes low image resolution and image deterioration, thereby adversely affecting the copy quality. In color systems, additional adverse results include color shifting and color deterioration. Ion transfer also increases the resistivity of the polymer member after repetitive use. This can limit the process and operational latitude, and eventually the ion-filled polymer member will be unusable.
Therefore, it is desired to provide a weldable intermediate transfer belt which has excellent transfer capability. It is also desired to provide a weldable intermediate transfer belt that may not have puzzle cut seams, but instead, has a weldable seam, thereby providing a belt or member other than a belt that can be manufactured without such labor intensive steps as manually piecing together the puzzle cut seam with ones fingers, and without the lengthy high temperature and high humidity conditioning steps.